Liquid crystal display device

ABSTRACT

An LCD device provides enhanced display quality. An insulating layer is formed on a first substrate. The insulating layer covers the contact portion of a switching device in which the switching device is electrically connected to a transparent electrode and has an opening for exposing a portion of the transparent electrode. A reflection electrode is electrically connected to the transparent electrode through the opening. The insulation layer covers a first portion of a driving circuit formed on the first substrate. A sealant is interposed between the first and second substrate to engage the first and second substrate and to cover a second portion of the driving circuit. Therefore, the driver circuit may operate normally, and the distortion of the signal outputted from the driver circuit may be prevented.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/088,839 filed on Apr. 18, 2013, which is acontinuation application of U.S. patent application Ser. No. 10/412,451filed on Apr. 11, 2003 and issued as U.S. Pat. No. 7,944,539 on May 17,2011, which claims priority to Korean Patent Application No.2003-0006189 filed on Jan. 30, 2003, the contents of which are hereinincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display (LCD) device,and more particularly to a liquid crystal display device having anenhanced display quality.

2. Description of the Related Art

An LCD device includes a first substrate, a second substrate and aliquid crystal layer interposed between the first and second substrates.When electric field is formed between the first and second substrates byan external electric signal, the alignment angles of the molecules ofthe liquid crystal layer are varied by the electric field, so that theLCD device displays an image.

The first substrate includes a display region through which the image isdisplayed and a peripheral region surrounding the display region. Aplurality of pixels is arranged in a matrix shape. Each of the pixelsincludes a gate line, a data line, a thin film transistor (TFT) and apixel electrode connected to the TFT.

A gate driver circuit for driving the gate of the TFT is disposed in theperipheral region, and the gate driver circuit may be formed on thefirst substrate through the process by which the TFT is formed on thefirst substrate. The gate driver circuit includes a plurality oftransistors, capacitors and wirings. An insulation film covers the gatedriver circuit. The insulation film has a contact hole. The insulationlayer includes a conduction layer that is electrically connected to theTFT through the contact hole. The conduction layer is disposed on theouter surface of the gate driver circuit.

The second substrate includes a common electrode facing the pixelelectrode, and the liquid crystal layer is formed between the commonelectrode and the pixel electrode. Since the common electrode is formedon an entire surface of the second substrate, the common electrode facesthe gate driver circuit, and the liquid crystal layer is formed betweenthe common electrode and the gate driver circuit. Accordingly, aparasite capacitance between the conduction layer and the commonelectrode exists.

The gate driver circuit may not normally operate due to the parasitecapacitance. The delay of the signal outputted from the gate drivercircuit may happen, and the distortion of the signal outputted from thegate driver circuit may happen. The display quality of the LCD devicemay be deteriorated due the parasite capacitance.

SUMMARY OF THE INVENTION

Accordingly, it is a feature of the present invention to provide a LCDdevice having an enhanced display quality.

In one aspect of the present invention, there is provided a liquidcrystal display device including a first substrate, a second substrate,a sealing member and a liquid crystal layer. The first substrateincludes a display part for displaying an image and a driver part fordriving the display unit. The second substrate faces the firstsubstrate. The sealing member is disposed between the first and secondsubstrates to engage the first substrate with the second substrate, andthe sealing member covers the driving part. The liquid crystal layer isdisposed between the first and second substrates.

In another aspect of the present invention, there is provided a liquidcrystal display device including a first substrate, a second substrateand a liquid crystal layer. The first substrate includes a display partfor displaying an image and a driver part for driving the display unit.The display part includes a switching device, a transparent electrode, afirst insulation and a reflection electrode. The transparent electrodeis electrically coupled with the switching device. The first insulationlayer is disposed on the transparent electrode to cover a contactportion of the switching device in which the switching device iselectrically coupled with the transparent electrode. The firstinsulation layer has an opening through which a portion of thetransparent electrode is exposed. The reflection electrode is disposedon the first insulation layer and is electrically coupled with thetransparent electrode at the opening. The second substrate includes acommon electrode facing the transparent electrode and the reflectionelectrode. The second substrate has a first portion and a secondportion. The driver part is disposed only under the first portion, thedriver part is not disposed under the second portion, and the commonelectrode is formed on the second portion of the second substrate. Theliquid crystal layer is disposed between the first and secondsubstrates.

As described above, according to the liquid crystal display device ofthis invention, the gate driver circuit formed in the first substrate iscovered by the insulation layer and (or sealant) having a dielectricconstant lower than that of the liquid crystal layer. In addition, thecommon electrode disposed over the gate driver circuit is removed.

The parasite capacitance between the gate driver circuit and the commonelectrode may be reduced. Therefore, the gate driver circuit may operatenormally, and the distortion of the signal outputted from the gatedriver circuit may be prevented. In addition, the LCD device may provideenhanced display quality.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail the preferredembodiments thereof with reference to the accompanying drawings, inwhich:

FIG. 1 is a plan view showing an example of a liquid crystal displaydevice of the present invention;

FIG. 2A is cross-sectional view showing a transmissive and reflectivetype liquid crystal display device according to a first exemplaryembodiment of the present invention;

FIG. 2B is cross-sectional view showing a transmissive type liquidcrystal display device according to a second exemplary embodiment of thepresent invention;

FIG. 3 is a cross-sectional view showing a liquid crystal display deviceaccording to a third exemplary embodiment of the present invention;

FIG. 4 is a block diagram showing the gate driver circuit of FIG. 3;

FIG. 5 is a layout showing each of the stage of the gate driver circuitof FIG. 3;

FIG. 6 is a cross-sectional view showing a liquid crystal display deviceaccording to a fourth exemplary embodiment of the present invention;

FIG. 7 is a cross-sectional view showing a liquid crystal display deviceaccording to a fifth exemplary embodiment of the present invention;

FIG. 8 is a cross-sectional view showing a liquid crystal display deviceaccording to a sixth exemplary embodiment of the present invention;

FIG. 9 is a cross-sectional view showing a liquid crystal display deviceaccording to a seventh exemplary embodiment of the present invention;

FIG. 10 is a plan view showing another example of a liquid crystaldisplay device of the present invention;

FIG. 11A is cross-sectional view showing a transmissive and reflectivetype liquid crystal display device according to an eighth exemplaryembodiment of the present invention;

FIG. 11B is cross-sectional view showing a transmissive type liquidcrystal display device according to a ninth exemplary embodiment of thepresent invention;

FIG. 12 is a cross-sectional view showing a liquid crystal displaydevice according to a tenth exemplary embodiment of the presentinvention;

FIG. 13 is a cross-sectional view showing a liquid crystal displaydevice according to an eleventh exemplary embodiment of the presentinvention; and

FIG. 14 is a cross-sectional view showing a liquid crystal displaydevice according to a twelfth exemplary embodiment of the presentinvention.

DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter preferred embodiment of the present invention will bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is a plan view showing an example of a liquid crystal displaydevice of the present invention. FIG. 2A is cross-sectional view showinga transmissive and reflective type liquid crystal display deviceaccording to a first exemplary embodiment of the present invention, andFIG. 2B is cross-sectional view showing a transmissive type liquidcrystal display device according to a second exemplary embodiment of thepresent invention.

Referring to FIGS. 1 and 2A, the liquid crystal display device accordingto a first exemplary embodiment of the present invention includes afirst substrate 100, a second substrate 200 facing the first substrate100 and a liquid crystal layer 300 interposed between the first andsecond substrate 100 and 200.

The first substrate 100 includes a display area (DA) through which animage is displayed and a peripheral area (PA) surrounding the displayarea (DA). The display area (DA) includes a plurality of pixels arrangedin a matrix shape. Each of the pixels includes a thin film transistor(TFT) 110 and a pixel electrode connected to the TFT 110. The TFT 110 isconnected to a gate line (GL) and a data line (DL). The data line (DL)is extended in a first direction, and the gate line (GL) is extended ina second direction substantially perpendicular to the first direction.The pixel electrode includes a transparent electrode 120 and areflection electrode 140.

As shown in FIG. 2A, the display area (DA) is divided into a reflectivearea (RA) and a transmissive area (TA). The reflection electrode 140 isformed in the reflective area (RA), and the first light generated froman external light source is reflected by the reflection electrode 140 inthe reflective area (RA). The transparent electrode 120 is formed in thetransmissive area (TA), and the second light generated from an internallight source of the LCD device is passed through the transparentelectrode 120 in the transmissive area (TA).

The TFT 110 is formed on the first substrate 100, an organic insulationlayer 130 having an embossing pattern is deposited on the firstsubstrate 100 on which the TFT 110 is formed. The organic insulationlayer 130 includes a contact hole 130 a through which a drain of the TFT110 is exposed.

The transparent electrode 120 is deposited on the organic insulationlayer 130. The transparent electrode 120 comprises indium tin oxide(ITO) or indium zinc oxide (IZO).

The reflection electrode comprises aluminum-neodymium (AlNd) having ahigh reflectivity, and is deposited uniformly on the transparentelectrode 120. The reflection electrode 140 has the same surface profileas the organic insulation layer 130. Accordingly, the reflectionefficiency of the reflection electrode 140 may be enhanced.

A gate driver circuit 160 is formed in the peripheral area (PA). Thegate driver circuit 160 is connected to an end of the gate line (GL) andsupplies a gate driving signal for driving the gate of the TFT 110. Thegate driver circuit 160 is electrically connected to the gate line (GL)disposed in the display area (DA) through the wiring 165. The gatedriver circuit 160 and the wiring 165 may be formed through the sameprocess in which the TFT 110 is formed in the display area (DA).

The second substrate 200 includes color filters 210 and a commonelectrode 220. The color filter 210 has red (R), green (G) and blue (B)color filters to display predetermined colors in combination of the red(R), green (G) and blue (B) colors. The common electrode 220 isdeposited uniformly on the color filter 210 and faces the transparentelectrode 120 and the reflection electrode 140.

The second substrate 200 is engaged with the first substrate 100 bysealant 350. The sealant 350 is disposed in the peripheral area (PA) andcovers the second portion (A2) of the gate driver circuit 160 except thefirst portion (A1) of the gate driver circuit 160.

The liquid crystal layer 300 is interposed between the first and secondsubstrates 100 and 200 that are engaged each other by the sealant 350,to thereby complete the LCD device 400.

The gate driver circuit 160 is covered by the sealant 350 having adielectric constant lower than that of the liquid crystal layer 300.Since the capacitance is in proportional to the dielectric constant andthe sealant 350 is interposed between the gate driver circuit 160 andthe common electrode 220, the capacitance between the gate drivercircuit 160 and the common electrode 220 may be reduced.

The above structure in which the sealant 350 and the gate driver circuit160 are arranged may be employed in the transmissive type LCD device.

As shown in FIG. 2B, the transmissive type LCD device has the sameperipheral area structure as the transmissive and reflective type LCDdevice of FIG. 2A. Although the above preferred embodiment shows theconfiguration according to the transmissive type LCD device shown inFIG. 2B, any other configurations known to one of the ordinary skill inthe art may also be utilized in place of the configuration according tothe transmissive type LCD device of FIG. 2B.

FIG. 3 is a cross-sectional view showing a liquid crystal display deviceaccording to a third exemplary embodiment of the present invention.

Referring to FIG. 3, the first substrate 100 includes a display area(DA) through which an image is displayed and a peripheral area (PA)surrounding the display area (DA). The display area (DA) includes aplurality of TFTs 110 and pixel electrodes connected to the TFTs 110.The pixel electrode 120 includes a transparent electrode 120 and areflection electrode 140. The transparent electrode 120 is directlyconnected to the TFT 110, and the reflection electrode 140 iselectrically connected to the TFT 110 through the transparent electrode120. While the TFT 110 is formed on the first substrate 100, thetransparent electrode 120 is directly connected to a drain (not shown)of the TFT 110. An organic insulation layer 130 is formed on the firstsubstrate 100 on which the TFT 110 and the transparent electrode 120 areformed. The organic insulation layer 130 covers a contact portion of theTFT 110 in which the TFT 110 is electrically connected to thetransparent electrode 120. The organic insulation layer 130 includes anopening 131 through which a portion of the transparent electrode 120 isexposed. The transmissive area (TA) corresponds to the opening 131.

The reflection electrode 140 is formed on the organic insulation layer130 and is electrically connected to the transparent electrode 120through the opening 131. In other words, the reflection electrode 140 isextended to a portion of the transparent electrode 120 that is exposedby the opening 131 and contacts with the transparent electrode 120.Accordingly, the reflection electrode 140 is electrically connected tothe drain of the TFT 110 through the transparent electrode 120.

A gate driver circuit 160 is formed in the peripheral area (PA). Thegate driver circuit 160 is connected to an end of the gate line (GL) andsupplies a gate driving signal for driving the gate of the TFT 110. Theorganic insulation layer 130 covers a first portion (A1) of the gatedriver circuit.

The sealant 350 is disposed in the peripheral area (PA) and covers thesecond and covers the second portion (A2) of the gate driver circuit 160except the first portion (Al) of the gate driver circuit 160.

The gate driver circuit 160 is covered by the sealant 350 and theorganic insulation layer 130. The sealant 350 and the organic insulationlayer 130 have dielectric constants lower than that of the liquidcrystal layer 300. Since the capacitance is in proportional to thedielectric constant and the sealant 350 and the organic insulation layer130 are interposed between the gate driver circuit 160 and the commonelectrode 220, the capacitance between the gate driver circuit 160 andthe common electrode 220 may be reduced.

FIG. 4 is a block diagram showing the gate driver circuit of FIG. 3, andFIG. 5 is a layout showing each of the stage of the gate driver circuitof FIG. 3.

Referring to FIG. 4, the gate driver circuit 160 includes a shiftregister 161. The shift register 161 includes a plurality of stages eachof which is cascade-connected.

An output terminal (OUT) of the present stage is connected to thecorresponding gate line and is connected to an input terminal (IN) ofthe next stage and a control terminal (CT) of the previous stage. Eachof the stages receives electric power VSS' and VDD′ through power lines,and clock signals ‘CK’ and ‘CKB’ through clock lines. Accordingly, eachof the stages outputs sequentially a gate driving signal having a highvoltage level to the corresponding gate lines.

Each of the stages includes a plurality of NMOS transistors NT1, NT2,NT3, NT4, NT5, NT6, and NT7 and a capacitor (C). Specifically, each ofthe stages includes a first conduction pattern 114 and a secondconduction pattern 115. The first conduction pattern 114 includes aplurality of gate electrodes of the NMOS transistors NT1, NT2, NT3, NT4,NT5, NT6, and NT7 and a first wiring extended from the gate electrodes.The second conduction pattern 115 includes a plurality of source anddrain electrodes of the NMOS transistors NT1, NT2, NT3, NT4, NT5, NT6,and NT7 and a second wiring extended from the source and drainelectrodes.

The first and second conduction patterns 114 and 115 is insulated eachother by a gate insulation layer. Since the organic insulation layer 130is formed on the second conduction pattern 115, each of the stagesrequires a conduction layer 117 for electrically connecting the firstconduction pattern 114 and the second conduction pattern 115.

Each of the stages includes first, second, third, fourth and fifthcontact hole regions CON1, CON2, CON3, CON4, and CON5. A gate electrodeof the first NMOS transistor NT1 is electrically connected to a sourceelectrode of the third NMOS transistor NT3 by the first contact holeregion CON1. A gate electrode of the second NMOS transistor NT2 iselectrically connected to a drain electrode of the seventh NMOStransistor NT7 by the second contact hole region CON2. A gate electrodeof the seventh NMOS transistor NT7 is electrically connected to a sourceelectrode of the third NMOS transistor NT3 by the third contact holeregion CON3. A gate electrode of the second NMOS transistor NT2 iselectrically connected to a source electrode of the sixth NMOStransistor NT6 by the fourth contact hole region CON4. A gate electrodeof the sixth NMOS transistor NT6 is electrically connected to a drainelectrode of the sixth NMOS transistor NT6 by the fifth contact holeregion CON5. The conduction layer 117 is formed so as to correspond tothe first, second, third, fourth and fifth contact hole regions CON1,CON2, CON3, CON4, and CON5.

Specifically, the gate electrode of the seventh NMOS transistor NT7 iselectrically connected to the source electrode of the third NMOStransistor NT3 through the third contact hole region CON3. An organicinsulation layer 130 has a first contact hole 141 and a second contacthole 143. The first contact hole 141 is formed on a portion of theorganic insulation layer 130 corresponding to the source electrode ofthe third NMOS transistor NT3. The first contact hole 141 exposes thegate electrode of the seventh NMOS transistor NT7. The second contacthole 143 is formed on another portion of the organic insulation layer130 corresponding to the drain electrode of the seventh NMOS transistorNT7. The second contact hole 143 exposes the source electrode of thethird NMOS transistor NT3. The conduction layer 117 is connected to thegate electrode of the seventh NMOS transistor NT7 and the sourceelectrode of the third NMOS transistor NT3 through the first and secondcontact holes 141 and 143. Accordingly, the conduction layer 117electrically connects the gate electrode of the seventh NMOS transistorNT7 and the source electrode of the third NMOS transistor NT3. Forexample, the conduction layer 117 comprises a transparent conductingmaterial such as indium tin oxide (ITO).

Although each of the stages of FIG. 5 shows the configuration includingNMOS transistors NT1, NT2, NT3, NT4, NT5, NT6, and NT7, each of thestages may include various configurations in place of the configurationof FIG. 5. Although each of the stages has other configurations in placeof the configuration of FIG. 5, each of the stages has the conductionlayer 117.

FIG. 6 is a cross-sectional view showing a liquid crystal display deviceaccording to a fourth exemplary embodiment of the present invention, andFIG. 7 is a cross-sectional view showing a liquid crystal display deviceaccording to a fifth exemplary embodiment of the present invention.

Referring to FIG. 6, in the display area (DA), the first substrate 100includes a TFT 110 and a pixel electrode, and the second substrate 200includes a color filter 210 and a common electrode 220. The pixelelectrode includes a reflection electrode 140 and a transparentelectrode 120 and is connected to the TFT 110.

Specifically, the first substrate 100 includes the TFT 110 having gateelectrode 111, source electrode 112 and drain electrode 113. Thetransparent electrode 120 is formed on the first substrate 100 on whichthe TFT 110 is formed. The transparent electrode 120 comprises ITO. Thetransparent electrode 120 is electrically connected to the drainelectrode 113. The transparent electrode 120 receives a signal that isapplied to the drain electrode of the TFT 110.

An organic insulation layer 130 is formed by a predetermined thicknesson the first substrate 100 on which the TFT 110 and the transparentelectrode 120. For example, the organic insulation layer 130 comprises aphotosensitive resin. The organic insulation layer 130 covers a contactportion of the drain electrode in which the drain electrode contactswith the transparent electrode 120. An opening 131 is formed on a firstportion of the organic insulation layer 130 for exposing a portion ofthe transparent electrode 120. The first portion of the organicinsulation layer 130 does not correspond to the contact portion of thedrain electrode in which the drain electrode contacts with thetransparent electrode 120. Accordingly, the reflectivity of thereflection electrode 140 may be enhanced.

The reflection electrode 140 is formed uniformly on the organicinsulation layer 130. For example, the reflection electrode 140comprises aluminum-neodymium (AlNd). The reflection electrode 140 iselectrically connected to the transparent electrode 120 through theopening 131. Accordingly, the reflection electrode 140 receives thesignal applied to the drain electrode 113 of the TFT 110 through thetransparent electrode 120.

A reflective area (RA) is referred to as an area by which the firstlight (L1) incident from the front surface of the LCD device 400 isreflected. A transmissive area (TA) is an area in which the transparentelectrode 120 is exposed. The transmissive area (TA) is referred to asan area through which the second light (L2) incident from the rearsurface of the LCD device 400 is transmitted.

Since the opening 131 is formed on the organic insulation layer 130, thereflective area (RA) of the LCD device 400 has a first cell gap (D1) andthe transmissive area (TA) of the LCD device 400 has a second cell gap(D2). In other words, the LCD device has the structure in which the cellgap of the reflective area (RA) is different from that of thetransmissive area (TA).

The liquid crystal layer 300 includes a first liquid crystal (not shown)adjacent to the second substrate 200 and a second liquid crystal (notshown) adjacent to the first substrate 100. A twist angle of the firstand second liquid crystal is referred to as the angle formed between themajor axis of the first and second liquid crystals and the a referenceline parallel to the first substrate.

The larger the twist angle is, the smaller has the transmissivity of theLCD device 400. Therefore, the second cell gap (D2) of the transmissivearea (TA) is double the first cell gap (D1) of the reflective area (RA)so as to compensate the difference of the light loss due to thepolarization characteristics of the LCD device. In the transmissive area(TA), the liquid crystal has a homogeneous alignment (or parallelalignment) so as to increase the transmissivity of the transmissive area(TA). In other words, the twist angle of the liquid crystal in thetransmissive area (TA) is substantially 0°.

As shown in FIG. 7, in display area (DA) of the LCD device according toa fifth exemplary embodiment of the present invention, the firstsubstrate 100 includes a TFT 110, a pixel electrode having a transparentelectrode 120 and a reflection electrode 140, an inorganic insulationlayer 150 and an organic insulation layer 130.

Specifically, the first substrate 100 includes the TFT 110 having gateelectrode 111, source electrode 112 and drain electrode 113. Theinorganic insulation layer 150 is formed on the first substrate 100 onwhich the TFT 110 is formed so as to protect the TFT 110. For example,the inorganic insulation layer 150 comprises a transparent inorganicmaterial such as silicon nitride (SiNx) or chrome oxide (Cr₂O₃). Theinorganic insulation layer 150 has a contact hole 151 for exposing thedrain electrode 113 of the TFT 110.

The transparent electrode 120 is formed on the inorganic insulationlayer 150. The transparent electrode 120 is electrically connected tothe drain electrode 113 through the contact hole 151. The transparentelectrode 120 receives a signal applied to the drain electrode 113 ofthe TFT 110.

The organic insulation layer 130 is formed by a predetermined thicknesson the first substrate 100 on which the TFT 110, inorganic insulationlayer 150 and the transparent electrode 120. For example, the organicinsulation layer 130 comprises a photosensitive acryl resin. An opening131 is formed on a first portion of the organic insulation layer 130 toexpose a portion of the transparent electrode 120. The first portion ofthe organic insulation layer 130 does not correspond to the contactportion of the TFT 110 in which the TFT 110 contacts with thetransparent electrode 120. Accordingly, the reflectivity of thereflection electrode 140 may be enhanced. An embossing pattern having aplurality of convex portions and concave portions is formed on thesurface of the organic insulation layer 130 so as to enhance thereflection efficiency of the reflection electrode 140.

The reflection electrode 140 is formed uniformly on the organicinsulation layer 130. For example, the reflection electrode 140comprises aluminum-neodymium (AlNd). The reflection electrode 140 iselectrically connected to the transparent electrode 120 through theopening 131. Accordingly, the reflection electrode 140 receives thesignal applied to the drain electrode 113 of the TFT 110 through thetransparent electrode 120.

Another contact hole for electrically connecting the reflectionelectrode 140 with the transparent electrode 120 and the drain electrode113 is not required since the reflection electrode 140 is electricallyconnected to the exposed transparent electrode 120 through the opening131. Therefore, the reflection efficiency of the reflection electrode140 may be enhanced. The reflection electrode 140 is formed on the uppersurface and the sidewall of the organic insulation layer 130 and also isextended onto the upper surface of the transparent electrode 120 so asto enhance the reflective efficiency of the reflection electrode.

A reflective area (RA) is referred to as an area by which the firstlight (L1) incident from the front surface of the LCD device 400 isreflected. A transmissive area (TA) is an area in which the transparentelectrode 120 is exposed. The transmissive area (TA) is referred to asan area through which the second light (L2) incident from the rearsurface of the LCD device 400 is transmitted.

The second substrate 200 includes a thickness-regulating member 230, acolor filter 210 and a common electrode 220 facing the transparentelectrode 120 and the reflection electrode 140. The color filter formedon the second substrate 200 has a first thickness (t1) in the reflectionarea (RA), and has a second thickness (t2) thicker than the firstthickness (t1). For example, the second thickness (t2) is twice thefirst thickness (t1).

The thickness-regulating member 230 is formed on a remained portion ofthe entire surface of the second substrate 200 except the portion of theentire surface of the second substrate 200 corresponding to thetransmissive area (TA). The thickness-regulating member 230 has a firstthickness (t1). The color filter 210 is formed on the second substrate200 on which the thickness-regulating member 230 is formed. The colorfilter may have a uniform surface. Accordingly, the color filter formedin the reflection area (RA) has a first thickness (t1) and has a secondthickness (t2) in the transmissive area (TA). The common electrode 220having a uniform thickness is formed on the color filter 210.

The first light (L1) is incident into the reflection area (RA) and isreflected by the reflection electrode 140. The first light (L1)transmits twice the color filter 210 having the second thickness (t2)and exits from the color filter 210. The second light (L2) transmit thetransmissive area (TA) and transmits one time the color filter 210having the second thickness (t2) and exits from the color filter 210.Therefore, the color reproduction in the reflection area (RA) issubstantially the same as the color reproduction in the transmissivearea (TA).

FIG. 8 is a cross-sectional view showing a liquid crystal display deviceaccording to a sixth exemplary embodiment of the present invention.

Referring to FIG. 8, the first substrate 100 includes the TFT 110 havinggate electrode 111, source electrode 112 and drain electrode 113. Atransparent electrode 120 comprised of indium tin oxide (ITO) is formedon the first substrate 100 on which the TFT 110 is formed. Thetransparent electrode is electrically connected to the drain electrode113. The transparent electrode 120 receives the signal applied to thedrain electrode 113 of the TFT 110.

The organic insulation layer 130 is formed by a predetermined thicknesson the first substrate 100 on which the transparent electrode 120 isformed. For example, the organic insulation layer 130 comprises aphotosensitive acryl resin. The organic insulation layer 130 covers thecontact portion of drain electrode 113 of the TFT 110 in which drainelectrode 113 of the TFT 110 makes contact with the transparentelectrode 120. An opening 131 is formed on a first portion of theorganic insulation layer 130 to expose a portion of the transparentelectrode 120. The first portion of the organic insulation layer 130does not correspond to the contact portion of the TFT 110 in which theTFT 110 makes contact with the transparent electrode 120.

A first reflection electrode 143 and a second reflection electrode 145are formed in the order named on the organic insulation layer 130. Thefirst reflection electrode 143 comprises molybdenum-tungsten (MoW). Thesecond reflection electrode 145 comprises aluminum-neodymium (AlNd). Thefirst reflection electrode 143 is electrically connected to thetransparent electrode 120 through the opening 131. The first reflectionelectrode 143 and second reflection electrode 145 receives the signalapplied to the drain electrode 113 of the TFT 110 through thetransparent electrode 120.

As shown in FIG. 8, the first reflection electrode 143 is interposedbetween the second reflection electrode 145 and the transparentelectrode 120 in the area where the opening 131 is formed. Accordingly,the electric cell reaction generated between the second reflectionelectrode 145 and the transparent electrode 143 may be prevented.

FIG. 9 is a cross-sectional view showing a liquid crystal display deviceaccording to a seventh exemplary embodiment of the present invention.FIG. 8 represents the reflective type LCD device, and is different fromthe first exemplary embodiment in that the display area (DA) has areflection area (RA) and does not has a transmissive area (TA).

Referring to FIG. 9, the light supplied from the external light sourceis reflected by the reflection electrode 140 in the reflection area(RA).

A sealant 350 has a dielectric constant lower than that of the liquidcrystal layer 300 and covers the gate driver circuit 160. Since thesealant 350 is interposed between the gate driver circuit 160 and thecommon electrode 220, a parasite capacitance between the gate drivercircuit 160 and the common electrode 220 may be reduced.

FIG. 10 is a plan view showing another example of a liquid crystaldisplay device of the present invention. FIG. 11A is cross-sectionalview showing a transmissive and reflective type liquid crystal displaydevice according to an eighth exemplary embodiment of the presentinvention, and FIG. 11B is cross-sectional view showing a transmissivetype liquid crystal display device according to a ninth exemplaryembodiment of the present invention. Throughout FIGS. 10, 11A and 11B,the same elements are designated by the same reference numerals of FIGS.1 and 3, and detailed descriptions about the identical elements areomitted.

Referring FIGS. 10 and 11A, the LCD device 500 includes a display area(DA) through which an image is displayed and a peripheral area (PA)surrounding the display area (DA).

A gate driver circuit 160 is formed in the peripheral area (PA). Thegate driver circuit 160 is connected to an end of the gate line (GL) andsupplies a gate driving signal for driving the gate of the TFT 110. Thegate driver circuit 160 is electrically connected to the gate line (GL)disposed in the display area (DA) through the wiring 165. The gatedriver circuit 160 and the wiring 165 may be formed through the sameprocess in which the TFT 110 is formed in the display area (DA).

The second substrate 200 is engaged with the first substrate 100 bysealant 350. The sealant 350 is disposed in the peripheral area (PA) andcovers entire surface of the gate driver circuit 160.

The liquid crystal layer 300 is interposed between the first and secondsubstrates 100 and 200 that are engaged with each other by the sealant350, to thereby complete the LCD device 500.

The sealant 350 has a dielectric constant lower than those of the liquidcrystal layer 300 and the organic insulation layer 130 formed on thedisplay area (DA) and the peripheral area (PA). The capacitance is inproportional to the dielectric constant, and the sealant 350 having adielectric constant lower than those of the liquid crystal layer 300 andthe organic insulation layer 130 is interposed between the gate drivercircuit 160 and the common electrode 220. The entire surface of the gatedriver circuit 160 is covered by the sealant 350, so that the parasitecapacitance between the gate driver circuit 160 and the common electrode220 may be reduced.

The above structure in which the sealant 350 and the gate driver circuit160 are arranged may be employed not only in the transmissive type LCDdevice but also in the reflective type LCD device (not shown) or in thetransmissive type LCD device (refer to FIG. 11B). Although FIG. 11Bshows the configuration of the transmissive type LCD device, any otherconfigurations known to one of the ordinary skill in the art may also beutilized in place of the configuration according to the transmissivetype LCD device of FIG. 11B.

FIG. 12 is a cross-sectional view showing a liquid crystal displaydevice according to a tenth exemplary embodiment of the presentinvention.

Referring to FIG. 12, the LCD device according to the tenth exemplaryembodiment of the present invention has the structure in which thecommon electrode is removed on a portion of the second substrate 200.The portion of the second substrate 200 is disposed over the gate drivercircuit 160 and the wiring 165. The common electrode 220 may be formedin a display area (DA) except the peripheral area (PA). In addition, thecommon electrode 220 may be further formed in the peripheral area (PA)in which the sealant 350 exists.

The portion of the common electrode 220 disposed over the gate drivercircuit 160 and the wiring 165 is etched away by a photolithographyprocess. Accordingly, the parasite capacitance generated in theperipheral area (PA) may be prevented.

In addition, the sealant and insulation layer having a dielectricconstant lower than that of the liquid crystal layer 300 covers the gatedriver circuit 160, and the insulation layer having a dielectricconstant lower than that of the liquid crystal layer 300 covers thewiring 165. In addition, the portion of the common electrode disposedover the gate driver circuit 160 is removed.

The parasite capacitance between the gate driver circuit and the commonelectrode may be reduced. Therefore, the gate driver circuit may operatenormally, and the distortion of the signal outputted from the gatedriver circuit may be prevented.

The structure of the common electrode in FIG. 12 may be employed notonly in the transmissive and reflective type LCD device, but also in areflective type LCD (not shown) device or in a transmissive type LCDdevice.

FIG. 13 is a cross-sectional view showing a liquid crystal displaydevice according to an eleventh exemplary embodiment of the presentinvention.

Referring to FIG. 13, the liquid crystal display device includes a firstsubstrate 100, a second substrate 200 facing the first substrate 100 anda liquid crystal layer 300 interposed between the first and secondsubstrate 100 and 200. The LCD device includes a display area (DA)through which an image is displayed and a peripheral area (PA)surrounding the display area (DA).

The display area (DA) includes a plurality of pixels arranged in amatrix shape. Each of the pixels includes a thin film transistor (TFT)110 and a pixel electrode connected to the TFT 110. The TFT 110 isconnected to a gate line (GL) and a data line (DL). The data line (DL)is extended in a first direction, and the gate line (GL) is extended ina second direction substantially perpendicular to the first direction.The pixel electrode includes a transparent electrode 120 and areflection electrode 140. The transparent electrode 120 is directlyconnected to the TFT 110, and the reflection electrode 140 iselectrically connected to TFT 110 through the transparent electrode 120.

An organic insulation layer 130 is formed on the first substrate 100 onwhich the TFT 110 and the transparent electrode 120 are formed. Theorganic insulation layer 130 covers a contact portion of the TFT 110 inwhich the TFT 110 is electrically connected to the transparent electrode120. The organic insulation layer 130 includes an opening 131 throughwhich a portion of the transparent electrode 120 is exposed. Thetransmissive area (TA) corresponds to the opening 131.

The reflection electrode 140 is formed on the organic insulation layer130 and is electrically connected to the transparent electrode 120through the opening 131. In other words, the reflection electrode 140 isextended to a portion of the transparent electrode 120 that is exposedby the opening 131 and makes contact with the transparent electrode 120.Accordingly, the reflection electrode 140 is electrically connected tothe drain of the TFT 110 through the transparent electrode 120.

A gate driver circuit 160 is formed in the peripheral area (PA). Thegate driver circuit 160 is connected to an end of the gate line (GL) andsupplies a gate driving signal for driving the gate of the TFT 110. Thegate driver circuit 160 is electrically connected to the gate line (GL)disposed in the display area (DA) through the wiring 165. The gatedriver circuit 160 and the wiring 165 may be formed through the sameprocess in which the TFT 110 is formed in the display area (DA). Theorganic insulation layer 160 having a dielectric constant lower thanthat of the liquid crystal layer 300 covers the entire surface of thegate driver circuit 160.

The second substrate 200 includes color filters 210 and a commonelectrode 220. The common electrode 220 is deposited uniformly on thecolor filter 210. The common electrode 220 is formed only in the displayarea (DA) and is not formed in the peripheral area (PA). However, thecommon electrode 220 may be further formed in the peripheral area (PA)where the sealant 350 exists.

The portion of the common electrode 220 disposed over the gate drivercircuit 160 is etched away by the photolithography process. Accordingly,the parasite capacitance generated in the peripheral area (PA) may beprevented.

FIG. 14 is a cross-sectional view showing a liquid crystal displaydevice according to a twelfth exemplary embodiment of the presentinvention.

Referring to FIG. 14, in the display area (DA), the first substrate 100includes TFT 110, pixel electrode, inorganic insulation layer 150 andorganic insulation layer 130. The pixel electrode includes a transparentelectrode 120 and a reflection electrode 130. In the display area (DA),the LCD device has the same structure as that of the LCD device of FIG.7. The first substrate 100 includes a second insulation layer. Thesecond insulation layer electrically connects the TFT 110 and thetransparent electrode 120.

The structure of the common electrode of FIGS. 11A and 11B may beemployed not only in the LCD device having the same structure of thedisplay area (DA) shown in FIGS. 11A and 11B but also the LCD devicehaving the same structure of the display area (DA) shown in FIGS. 2, 6and 8. In addition, the structure of the common electrode of FIGS. 11Aand 11B may be employed not only in the transmissive and the reflectivetype LCD device but also may be employed in a reflective type LCD deviceor a transmissive type LCD device.

While the exemplary embodiments of the present invention and itsadvantages have been described in detail, it should be understood thatvarious changes, substitutions and alterations can be made hereinwithout departing from the scope of the invention as defined by appendedclaims.

1. A liquid crystal display device comprising: a first substratecomprising a display part comprising a switching element and a pixelelectrode electrically connected to the switching element to display animage and a driver part comprising a plurality of transistors configuredto drive the display part; a second substrate facing the firstsubstrate; a sealing member disposed between the first and secondsubstrates and covering at least a portion of the driver part; and aliquid crystal layer disposed between the first and second substrates,wherein the switching element of the display part comprises: a gateelectrode; a gate insulation layer covering the gate electrode; a sourceelectrode disposed on the gate insulation layer; and a drain electrodedisposed on the gate insulation layer and spaced apart from the sourceelectrode, wherein the driver part comprises: a first conductive patterncomprising gate electrode for the transistors; a second conductivepattern comprising a source electrode and a drain electrode for thetransistors and disposed in a different layer from the first conductivepattern; an insulation layer that covers the first conductive patternand the second conductive pattern and comprises a first contact holeoverlapping the first conductive pattern and a second contact holeoverlapping the second conductive pattern; and a connection layerelectrically connecting the first conductive pattern and the secondconductive pattern through the first contact hole and the second contacthole and comprising a transparent conductive material.
 2. The liquidcrystal display device of claim 1, wherein the sealing member entirelycovers the driver part.
 3. The liquid crystal display device of claim 1,wherein the second substrate further comprises a common electrode facingthe pixel electrode.
 4. The liquid crystal display device of claim 3,wherein the common electrode does not overlap the driver part.
 5. Theliquid crystal display device of claim 1, wherein the first substratefurther comprises a gate line and a data line, which are electricallyconnected to the switching element.
 6. The liquid crystal display deviceof claim 1, wherein the driver part is configured to receive an electricpower and a clock signal to generate and output a gate driving signal tothe gate line.
 7. The liquid crystal display device of claim 1, whereinthe insulation layer comprises an organic insulation layer.
 8. Theliquid crystal display device of claim 1, wherein the first conductionpattern comprises a gate electrode of a first transistor and an endcontacting the connection layer, and the second conduction patterncomprises a first end contacting the connection layer and a second end,which is a source electrode of a second transistor.
 9. The liquidcrystal display device of claim 1, wherein the gate electrode of thedriver part overlap the source electrode and the drain electrode of thedriver part in a plan view.
 10. The liquid crystal display device ofclaim 1, wherein the transparent conductive material comprises indiumtin oxide or indium zinc oxide.
 11. The liquid crystal display device ofclaim 1, wherein the transistors of the driver part and the switchingelement of the display part are formed in a same process.